Impacts of topography and land cover change on thunderstorm over the Huangshan (Yellow Mountain) area of China

Abstract

In this study, the Weather Research and Forecasting (WRF) model (version 3.1.1) was used to simulate a thunderstorm event which occurred on August 18, 2010, over the Yellow Mountain area of China. This event was a typical thunderstorm embedded in high-pressure systems. First, the development processes of mountain–valley breeze and convective cells were studied; second, this study focused on revealing the influencing mechanism of complex topography and heterogeneous land cover on thunderstorm by removing the Yellow Mountain and changing the land use categories. On flat terrain, the simulated results displayed that the convection weakened persistently, cloud top decreased sharply, and intensity of precipitation reduced. Moreover, there was no up-slope valley breeze, convergence, and lifting of water vapor could be found on the mountaintop. Then, the role of land use was revealed by changing original land cover into grassland, mixed forests, and bare soil in the innermost area, respectively. When covered by grassland, there were less sensible heating and lower moisture, leading to the planet boundary layer height decreasing and vertical lifting weakening, which tended to cause more stable atmosphere and less rainfall on the mountaintop; when covered by mixing forests, only small differences presented in simulated meteorological fields, including wind fields, moisture, cloud water mixing ratio, precipitation, and other fields; when covered by bare soil, the latent heating was more important in influencing the process of thunderstorm. There were less latent heating and lower accumulated water vapor compared to other experiments, causing vertical lifting weakening, stability of atmosphere increasing, and precipitation decreasing.